export default {
    namespaced: true,

    state: () => ({
        cart: JSON.parse(uni.getStorageSync('cart') || '[]'),
    }),

    mutations: {
        addToCart(state, goods) {
            const findResult = state.cart.find((x) => x.goods_id === goods.goods_id)

            if (!findResult) {
                state.cart.push(goods)
            } else {
                findResult.goods_count++
            }
            this.commit('m_cart/saveToStorage')
        },
        saveToStorage(state) {
            uni.setStorageSync('cart', JSON.stringify((state.cart)))
        },
        updateGoodsState(state, goods) {
            const findResult = state.cart.find(x => x.goods_id === goods.goods_id)

            if (findResult) {
                findResult.goods_state = goods.goods_state

                this.commit('m_cart/saveToStorage')
            }
        },
        updateGoodsCount(state, goods) {
            const findResult = state.cart.find(x => x.goods_id === goods.goods_id)

            if (findResult) {
                findResult.goods_count = goods.goods_count
                this.commit('m_cart/saveToStorage')
            }
        },
        removeGoodsById(state, goods_id) {
            state.cart = state.cart.filter(x => x.goods_id !== goods_id)

            this.commit('m_cart/saveToStorage')
        },
        updateAllGoodsState(state, newState) {
            state.cart.forEach(x => x.goods_state = newState)
            this.commit('m_cart/saveToStorage')
        },

    },

    getters: {
        total(state) {
            let c = 0
            state.cart.forEach(x => c += x.goods_count)
            return c
        },
        checkedCount(state) {
            return state.cart.filter(x => x.goods_state).reduce((total, item) =>
                total += item.goods_count, 0)
        },
        // 已勾选的商品的总价
        checkedGoodsAmount(state) {
            // 先使用 filter 方法，从购物车中过滤器已勾选的商品
            // 再使用 reduce 方法，将已勾选的商品数量 * 单价之后，进行累加
            // reduce() 的返回值就是已勾选的商品的总价
            // 最后调用 toFixed(2) 方法，保留两位小数
            return state.cart.filter(x => x.goods_state)
                .reduce((total, item) => total += item.goods_count *
                    item.goods_price, 0)
                .toFixed(2)
        },
    }
}